U.S. patent number 7,523,742 [Application Number 10/580,311] was granted by the patent office on 2009-04-28 for combustion gas seal for fuel injection valve.
This patent grant is currently assigned to NOK Corporation, Toyota Jidosha Kabushiki Kaisha. Invention is credited to Junichi Nakayama, Kenji Ohkubo, Iwao Taira, Tomihisa Tsuchiya, Masaaki Yano.
United States Patent |
7,523,742 |
Tsuchiya , et al. |
April 28, 2009 |
Combustion gas seal for fuel injection valve
Abstract
Leakage of a combustion gas is prevented by installing a seal
ring in an annular groove provided in the outer peripheral surface
of a fuel injection valve. Further, a combustion gas leaked from
the seal ring is sealed in by providing a seal washer more on the
rear end side of the fuel injection valve than the seal ring. Thus
a combustion gas seal for an injection valve is provided, and the
combustion gas seal is capable of exhibiting excellent sealing
ability for a long term with a simple structure.
Inventors: |
Tsuchiya; Tomihisa (Toyota,
JP), Ohkubo; Kenji (Toyota, JP), Yano;
Masaaki (Nishikamo-gun, JP), Taira; Iwao
(Nihonmatsu, JP), Nakayama; Junichi (Fujisawa,
JP) |
Assignee: |
Toyota Jidosha Kabushiki Kaisha
(Aichi, JP)
NOK Corporation (Tokyo, JP)
|
Family
ID: |
34631433 |
Appl.
No.: |
10/580,311 |
Filed: |
October 22, 2004 |
PCT
Filed: |
October 22, 2004 |
PCT No.: |
PCT/JP2004/015727 |
371(c)(1),(2),(4) Date: |
April 02, 2007 |
PCT
Pub. No.: |
WO2005/052360 |
PCT
Pub. Date: |
June 09, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070272214 A1 |
Nov 29, 2007 |
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Foreign Application Priority Data
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Nov 25, 2003 [JP] |
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2003-393553 |
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Current U.S.
Class: |
123/470 |
Current CPC
Class: |
F02M
61/14 (20130101); F02M 61/167 (20130101); F02M
61/168 (20130101); F02M 2200/06 (20130101); F02M
2200/858 (20130101) |
Current International
Class: |
F02M
61/14 (20060101) |
Field of
Search: |
;123/470 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1326022 |
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Jul 2003 |
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EP |
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04-086371 |
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Mar 1992 |
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JP |
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11-210600 |
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Aug 1999 |
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JP |
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11-294302 |
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Oct 1999 |
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JP |
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2002-257239 |
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Sep 2002 |
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JP |
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2003-343727 |
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Mar 2003 |
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JP |
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2004-036775 |
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Feb 2004 |
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JP |
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2004-239124 |
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Aug 2004 |
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JP |
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2005-098238 |
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Apr 2005 |
|
JP |
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Other References
Japanese Office Action dated May 7, 2008 and English translation.
cited by other.
|
Primary Examiner: Cronin; Stephen K
Assistant Examiner: Castro; Arnold
Attorney, Agent or Firm: Jacobson Holman PLLC
Claims
The invention claimed is:
1. A combustion-gas seal for a fuel injection system comprising an
annular clearance gap between a mounting hole provided in a housing
and a fuel injection valve mounted in the mounting hole, a main
seal ring of resin installed in an annular groove provided on an
outer peripheral surface of the fuel injection valve and far from a
tip side of the fuel injection valve, the main seal ring having an
elastic recovery feature, a seal washer sandwiched between the
housing and the fuel injection valve at a position toward a rear
end of the fuel injection valve from the seal ring, the seal washer
including a metal ring and a rubber-like elastic portion fitted to
the metal ring, the rubber-like elastic portion fitting an outer
peripheral surface of the metal ring with the rubber-like elastic
portion being located radially outwardly from the metal ring with
respect to a mounting direction of the fuel injection valve, and a
heat-resistant ring of resin installed in a second annular groove
provided at a position toward the tip side of the fuel injection
valve from the annular groove, and having approximately a same
outside diameter as that of the seal ring.
Description
This is a nationalization of PCT/JP04/015727 filed Oct. 22, 2004
and published in Japanese.
TECHNICAL FIELD
The present invention relates to a combustion-gas seal for a fuel
injection valve, the seal preventing leakage of combustion gas by
sealing an annular clearance gap between the fuel injection valve
and a mounting hole therefor.
BACKGROUND ART
A direct injection engine has adopted a configuration in which a
fuel injection valve is mounted onto a mounting hole in a cylinder
head (housing), and fuel is injected directly into a cylinder from
a nozzle at the tip of this fuel injection valve. Accordingly, it
is required to prevent leakage of combustion gas at high pressure
from an annular clearance gap between the fuel injection valve and
the mounting hole.
A structure in which an annular groove is provided on an outer
peripheral surface of the fuel injection valve, and a rubber or
resin seal ring is installed into the annular groove has been known
as a sealing structure against the leakage (refer to patent
documents 1 through 6). Moreover, a configuration in which two
kinds of seal rings, rubber and resin, are combined has been
proposed in a patent document 7, and a configuration in which a
metal ring is arranged on the tip side of a rubber O-ring has been
proposed in a patent document 8.
[Patent Document 1]: Japanese Laid-Open Patent Application
Publication No. 2002-070696,
[Patent Document 2]: Japanese Laid-Open Patent Application
Publication No. 2002-081548,
[Patent Document 3]: Japanese Laid-Open Patent Application
Publication No. 2002-081549,
[Patent Document 4]: Japanese Laid-Open Patent Application
Publication No. 2002-202030,
[Patent Document 5]: Japanese Laid-Open Patent Application
Publication No. 2002-317733,
[Patent Document 6]: Japanese Laid-Open Patent Application
Publication No. 2002-364494,
[Patent Document 7]: Japanese Laid-Open Patent Application
Publication No. 11-013593, and
[Patent Document 8]: Japanese Laid-Open Patent Application
Publication No. 2000-310332.
DISCLOSURE OF THE INVENTION
Problems that this Invention is to Solve
When an engine is operated, the tip portion of a fuel injection
valve is always exposed to combustion gas at high temperature and
high pressure. Therefore, damage of a seal ring installed in the
tip portion of the fuel injection valve proceeds comparatively
fast, and sealing ability easily becomes unstable. Especially, a
seal of resin such as PTFE (polytetrafluoroethylene) has had a
problem that the sealing ability is remarkably degraded at low
temperature to cause a large quantity of leakage.
Here, it is also considered that the position of the seal is
configured to be held away from the tip portion of the fuel
injection valve for control of damage of the seal. However, the
temperature of the tip portion of a fuel injection valve remarkably
rises in the above case because an entering quantity of combustion
gas into an annular clearance gap is increased. Then, a deposit,
which adheres to the neighborhood of the fuel injection nozzle of
the fuel injection valve, is increased to cause a malfunction such
as reduction in the injecting quantity of fuel and deterioration in
the fuel injecting response in some cases.
Moreover, the damage of a seal is considered to be controlled by
installing two seal rings in the tip portion of the fuel injection
valve, as proposed in the patent documents 7 and 8. However, the
above configuration is not preferable because steps for assembling
the seal onto the fuel injection valve are increased to cause
reduction in the productivity. Especially, a resin seal with a low
elastic recovery requires a correcting step at installation of the
seal into an annular groove, while an enlarged diameter is returned
to an original one at the correcting-step (refer to the patent
document 6). Accordingly, the increase in the number of seals
causes remarkable reduction in the productivity.
The present invention has been made, considering the above
circumstances, and one of its objects is to provide a
combustion-gas seal for a fuel injection valve with a simple
configuration, wherein the seal can exhibit an excellent sealing
ability for a long term.
Moreover, another object of the present invention is to provide a
combustion-gas seal for a fuel injection valve, wherein the seal
can realize both maintenance of the sealing ability of the seal,
and control of temperature rise at the tip portion of the fuel
injection valve.
Further another object of the present invention is to provide a
combustion-gas seal for a fuel injection valve, wherein the seal
can reduce steps for assembling a plurality of seals onto the fuel
injection valve and can improve the productivity.
Means for Solving the Problems
The combustion-gas seal for a fuel injection valve according to the
present invention seals an annular clearance gap between a mounting
hole provided in a housing such as a cylinder head and a fuel
injection valve mounted in the mounting hole, and adopts the
following configurations.
The present invention is provided with a seal ring installed into
an annular groove provided on the outer peripheral surface of a
fuel injection valve. This seal ring prevents leakage of combustion
gas by seal contact with the bottom surface of the annular groove
and the peripheral surface of the mounting hole.
The present invention may have a configuration in which a seal
washer is sandwiched between the housing and the fuel injection
valve at a position toward the rear end of the fuel injection valve
from the seal ring. Thereby, the seal washer can function as a
secondary seal, and combustion gas which leaks from the seal ring
can be surely sealed by the seal washer. Accordingly, a sealing
ability of the whole combustion-gas seal for a fuel injection valve
is improved, and an excellent sealing ability is realized for a
long term.
Moreover, the position at which the seal ring is installed may be
set, by providing the seal washer as a secondary seal, at a
position toward the tip of the fuel injection valve, because the
allowable damaged and leakage ranges of the seal ring itself may be
extended. Then, an advantage that temperature rise at the tip
portion of the fuel injection valve is controlled may be
expected.
Furthermore, as the fuel injection valve is fastened into the
housing, the seal washer is simultaneously sandwiched (assembled).
Accordingly, steps for assembling the seal onto the fuel injection
valve are not increased. That is, addition of the seal washer does
not cause reduction in the productivity.
Here, the seal washer preferably has a metal ring and a rubber-like
elastic portion which is fitted to the metal ring by baking. Since
the rubber-like elastic portion is provided, an followability to a
seal surface (a housing wall surface and/or the wall surface of a
fuel injection valve) and high degree of adhesion thereto are
improved, and preferable sealing ability is realized.
The present invention is preferably provided with a heat-resistant
ring installed into a second annular groove provided at a position
toward the tip side of the fuel injection valve from the annular
groove. Since the heat-resistant ring is provided, the entering
quantity of combustion gas into the annular clearance gap can be
reduced. Since the load put on the seal ring can be reduced, damage
of the seal ring can be controlled and an excellent sealing ability
can be realized for a long term.
Moreover, since temperature rise at the tip portion of the fuel
injection valve is controlled by providing the heat-resistant ring,
adhesion of deposit can be prevented, and stable movement of the
fuel injection valve can be maintained.
Here, the seal ring and the heat-resistant ring preferably have
approximately the same outside diameter. The above configuration
enables shareability of an installing jig, which installs a ring
into a groove of the fuel injection valve, while the inside
diameter of the ring is being extended, and a correcting jig, which
corrects the diameter which has been extended when the ring is
installed, between the seal ring and the heat-resistant ring.
Accordingly, the seal ring and the heat-resistant ring can be
sequentially installed and corrected, using one set of the
installing jig and the correcting jig, that is, step reduction and
improved productivity can be realized.
For example, the following assembling methods can be adopted. Here,
the after-described assembling methods may be preferably applied
not only to a case in which a seal ring and a heat-resistant ring
are assembled onto a fuel injection valve, but also to a case in
which two or more rings with approximately the same outside
diameter are assembled onto one member.
An assembling method by which a first ring (seal ring) is assembled
into a first annular groove of the member (fuel injection valve),
and a second ring (heat-resistant ring) with approximately the same
outside diameter as that of the first ring is assembled into a
second annular groove provided at a position toward the tip side of
the member from the first annular groove has the following steps
of:
arranging a correcting jig at a position toward the rear end of the
member from the first ring;
arranging an installing jig, which covers the second annular
groove, at a position at which the first ring can be led into the
first annular groove;
installing the first ring into the first annular groove, using the
installing jig;
relatively sliding the installing jig to a position at which the
second ring can be led into the second annular groove;
correcting the first ring by relatively sliding the correcting jig
to a position for installing the first ring;
installing the second ring into the second annular groove by means
of the installing jig during the correction of the first ring;
and
correcting the second ring by relatively sliding the correcting jig
to a position for installing the second ring.
Here, "relatively sliding" means that a jig or a member, or the
both of them may be slidden.
EFFECT OF THE INVENTION
According to the combustion-gas seal for a fuel injection valve of
the present invention, excellent sealing ability may be realized
for a long term with a simple structure.
Moreover, both maintenance of the sealing ability and control of
temperature rise in the tip portion of a fuel injection valve may
be simultaneously obtained.
Furthermore, step reduction and improved productivity can be
realized, when a plurality of seals are assembled onto a fuel
injection valve.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a view showing a state in which a combustion-gas seal for
a fuel injection valve according to a first embodiment of the
present invention is assembled onto a fuel injection valve;
FIG. 2A is a view explaining a method by which a seal ring and a
heat-resistant ring are assembled onto a fuel injection valve;
FIG. 2B is a view explaining a method by which a seal ring and a
heat-resistant ring are assembled onto a fuel injection valve;
FIG. 2C is a view explaining a method by which a seal ring and a
heat-resistant ring are assembled onto a fuel injection valve;
FIG. 2D is a view explaining a method by which a seal ring and a
heat-resistant ring are assembled onto a fuel injection valve;
and
FIG. 3 is a view showing a state in which a combustion-gas seal for
a fuel injection valve according to a second embodiment of the
present invention is assembled onto a fuel injection valve.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, preferable embodiments according to the present
invention will be illustratively explained in detail, referring to
drawings. However, with regards to sizes, materials, shapes, and
relative arrangements, and the like for components described in the
embodiments, the scope of the present invention are not limited to
the above embodiments, unless otherwise specified.
First Embodiment
FIG. 1 is a view showing a state in which a combustion-gas seal for
a fuel injection valve according to a first embodiment of the
present invention is assembled onto a fuel injection valve.
The combustion-gas seal 2 for a fuel injection valve (hereinafter,
simply called "combustion-gas seal") prevents leakage of combustion
gas from the side near a cylinder (right-hand side in the drawing)
by sealing an annular clearance gap between a mounting hole 40
provided in a cylinder head (housing) 4 of a direct injection
engine and a fuel injection valve 5 mounted in the mounting hole
40.
The combustion-gas seal 2 according to the present embodiment
includes a seal ring 10 as a main seal, and a heat-resistant ring
12 as a thermoprotector.
The seal ring 10 is a seal ring with a rectangular cross section,
and the ring is installed into an annular groove 51 provided on the
outer peripheral surface at the tip portion of the fuel injection
valve 5. A rubber-like elastic material or a resin material may be
used as the material of the seal ring 10, but, considering the
temperature and the components and the like of the combustion gas,
it is preferable to use a heat-resistant material with a high
resistance to chemicals. For example, PTFE
(polytetrafluoroethylene) may be preferably used.
The inside diameter of the seal ring 10 is set to be a little
smaller than the diameter of the bottom surface of the annular
groove 51, and the outside diameter is also set to be slightly
larger than the diameter of the peripheral surface of the mounting
hole 40, wherein the surface is opposing to the annular groove 51.
Because the seal ring 10 has such a squeeze, when the fuel
injection valve 5 is mounted into the mounting hole 40, compressive
deformation is caused in the seal ring 10, and the seal ring comes
hermetically contact with the bottom surface of the annular groove
51 and the peripheral surface of the mounting hole 40 due to an
elastically recovering force. Thereby, the leakage of the
combustion gas from the cylinder side is prevented.
Moreover, in the present embodiment, the annular groove 51 is
provided with a tapered portion 52 on the bottom surface thereof,
and the tapered portion is configured such that closer to the rear
end of the fuel injection valve (left-hand side in the drawing),
the depth of the groove become shallower. Thereby, when the
pressure of the combustion gas is applied to the seal ring 10, and
the ring 10 is moved backward in the groove, the degree of adhesion
by the seal ring 10 is improved to cause better sealing
ability.
The heat-resistant ring 12 is a ring-like member with a rectangular
cross section, wherein the member is installed into a second
annular groove 54 provided at a position toward the tip side of a
fuel injection valve from an annular groove 51 in which the seal
ring 10 is installed. The heat-resistant ring 12 reduces the
entering quantity of combustion gas into an annular clearance gap
in the vicinity of the tip end of the fuel injection valve 5.
The heat-resistant ring 12 is preferably arranged in the vicinity
of the tip end of the fuel injection valve 5 in order to enhance
the reducing effect of the entering quantity of the fuel gas. On
the other hand, the seal ring 10 is preferably configured to be
held away to a certain degree from the tip end of the fuel
injection valve 5 for control of damage by fuel gas.
According to the configuration in the present embodiment, damage of
the seal ring 10 can be controlled and an excellent sealing ability
can be realized for a long term, because the heat-resistant ring 12
reduces the entering quantity of combustion gas to reduce load put
on the seal ring 10.
Moreover, since temperature rise at the tip portion of the fuel
injection valve is controlled by providing the heat-resistant ring
12, adhesion of deposit can be prevented, and stable movement of
the fuel injection valve 5 can be maintained.
Considering the temperature, the components, and the like of the
combustion gas, it is preferable to use a high heat-resistant
material with a high resistance to heat and chemicals as the
material of the heat-resistant ring 12. For example, a resin
material such as PTFE (polytetrafluoroethylene) may be preferably
used.
Since the heat-resistant ring 12 is required only to have sealing
ability necessary and sufficient for reduction in the entering
quantity of combustion gas, a squeeze may be provided, or may not
be provided. When the squeeze is provided, the reducing effect of
the entering quantity of combustion gas is enhanced, because the
sealing ability of the heat-resistant ring 12 is improved. On the
other hand, when the squeeze is not provided, there is an advantage
that the fuel injection valve 5 can be more easily assembled into a
mounting hole 40. Moreover, it is preferable to improve the sealing
ability of the heat-resistant ring 12 by providing a tapered
portion similar to that of the annular groove 51 on the bottom
surface of the second annular groove 54.
In the present embodiment, the outside diameter of the
heat-resistant ring 12 is configured to be approximately the same
as that of the seal ring 10 (regardless of the presence of the
squeeze). The above configuration enables shareability of an
installing jig and a correcting jig, and reduction in the number of
assembling steps is realized.
Then, a method for assembling the seal ring 10 and the
heat-resistant ring 12 onto the fuel injection valve will be
specifically explained, referring to FIG. 2A through FIG. 2D.
As shown in FIG. 2A and FIG. 2B, an installing jig 6 installs a
ring into a groove of the fuel injection valve 5, while the inside
diameter of the ring is being extended. The diameter of the
installing jig 6 at the lead-in side (upper side in the drawing)
for the ring is configured to be enough smaller than the inside
diameter of the ring. Then, the diameter of the installing jig 6
gradually becomes larger from the middle thereof toward the side
(lower side in the drawing), near the position on which the ring is
installed, in a conical manner. A cylinder portion is provided at
the lower end of the installing jig 6, and the ring can be led into
the groove by covering the tip portion of the fuel injection valve
with the cylinder portion.
On the other hand, a correcting jig 7 corrects the diameter which
has been extended when the ring is installed. The correcting jig 7
has a correcting hole 70 in accordance with the (original) outside
diameter of the ring. The correcting jig 7 is supported by a base
71 in such a way that the jig 7 can be slidden in the axis
direction (vertical direction in the drawing) of the fuel injection
valve 5 and a correcting jig assembly 72 includes the correcting
jig 7 and the base 71.
As shown in FIG. 2A, the fuel injection valve 5 is inserted into
the correction hole 70 of the correcting jig 7 in the first place
for positioning. At this time, the correcting jig 7 is arranged in
the annular groove 51 at the side (lower side in the drawing) near
the rear end of the fuel injection valve.
Then, the installing jig 6 is put onto the tip portion of the fuel
injection valve 5 for positioning. At this time, the installing jig
6 covers the
And, while the inside diameter of the seal ring 10 is gradually
extended by leading the seal ring 10 onto the installing jig 6 and
by sliding the ring along the peripheral surface of the installing
jig 6 from the lead-in side, the seal ring 10 is installed into the
annular groove 51. Since the ring of the resin material has low
elasticity, it is not easy to return the diameter to the initial
one only by the elastically recovering force of its own.
Then, after installing the seal ring 10, the correcting jig 7 is
relatively slidden to an installing position of the seal ring 10 as
shown in FIG. 2B, and correction of the seal ring 10 is
executed.
As the correction is executed, the installing jig 6 is relatively
slidden in a simultaneous manner to a position at which the
heat-resistant ring 12 can be led into the second annular groove
54, and the heat-resistant ring 12 is installed into the second
annular groove 54 during the correction of the seal ring 10.
After installing the heat-resistant ring 12, the installing jig 6
is removed, as shown in FIG. 2C, and the fuel injection valve 5 and
the correcting jig 7 are sudden downward for positioning of the
fuel injection valve 5 at the position.
Then, the heat-resistant ring 12 is corrected by relatively sliding
the correcting jig 7 to a position for installing the
heat-resistant ring 12, as shown in FIG. 2D, after completing the
correction of the seal ring 10.
According to the above-described assembling method, the seal ring
10 and the heat-resistant ring 12 can be sequentially installed and
corrected, and the heat-resistant ring 12 can be installed during
correction of the seal ring 10, using one set of the installing jig
and the correcting jig. Accordingly. step reduction and improved
productivity can be realized.
Second Embodiment
FIG. 3 is a view showing a state in which a combustion-gas seal for
a fuel injection valve according to a second embodiment of the
present invention is assembled onto a fuel injection valve. In FIG.
3, portions similar to those in the above-described first
embodiment (FIG. 1) are denoted by the same reference numerals as
those in FIG. 1 and FIG. 2.
A combustion-gas seal 3 according to the present embodiment
includes a seal ring 10 as a main seal, a seal washer 11 as a
secondary seal, and a heat-resistant ring 12 as a thermoprotector.
Configurations of the seal ring 10 and the heat-resistant ring 12
in the present embodiment are similar to those in the
above-described embodiments.
A seal washer 11 includes a metal ring 11a, and a rubber-like
elastic portion 11b which is fitted to the outer peripheral surface
of the metal ring 11a by baking. Considering the environments
around an engine room, a material with a heat resistance up to
about 120.degree. C. through 150.degree. C. is preferable as a
material for the rubber-like elastic portion 11b on a higher
temperature side. Moreover, a material which can exhibit the
rubber-like elasticity even at about -40.degree. C. is preferable
for a lower temperature side.
The seal washer 11 is sandwiched and fixed between the cylinder
head 4 and the fuel injection valve 5 at a position toward the rear
end of the fuel injection valve from the seal ring 10. That is,
when the fuel injection valve 5 is fastened into the cylinder head
4, the seal washer 11 is configured to be fixed by holding the
metal ring 11a between the step surface 53 of the fuel injection
valve 5 and the step surface 41 of the mounting hole 40, those
surfaces are extended in a direction approximately perpendicularly
to the mounting direction (direction indicated by an arrowhead in
the drawing) of the fuel injection valve.
In the present embodiment, the sectional shape of the metal ring
11a is configured to be a U-shape opening inwardly on the inner
peripheral surface. Thereby, when the metal ring 11a is sandwiched
between two step surfaces 53 and 41, the ring 11a is compressed and
deformed in the mounting direction of the fuel injection valve, and
applies strong pressing force to the step surfaces 53 and 41 by the
elastically recovering force. That is, the metal ring 11a functions
as a metal leaf spring to improve the stability for installing the
seal washer 11.
When the washer 11 is fixed as described above, the rubber-like
elastic portion 11b is adhered to the step surfaces 53 and 41.
Since the rubber-like elastic portion 11b is very elastic, the
rubber-like elastic portion 11b has an excellent followability to
the step surfaces 53 and 41 as a seal surface and high degree of
adhesion thereto, that is, preferable sealing ability is
realized.
At this time, it is further preferable to add a lip to the
rubber-like elastic portion 11b. That is, the lip has a
configuration in which the width of at least a part of the
rubber-like elastic portion 11b in the mounting direction of the
fuel injection valve is wider than that of the metal ring 11a to
secure a squeeze for the step surfaces 53 and 41. Thereby, when the
rubber-like elastic portion 11b is sandwiched between the step
surfaces 53 and 41, the rubber-like elastic portion 11b is
compressed in the mounting direction of the fuel injection valve,
and adhesion force to the step surfaces 53 and 41 is increased by
the elastically recovering force (so-called self-sealing function).
Accordingly, the sealing ability may be further improved.
According to the configuration in this embodiment described above,
the seal washer 11 can function as a secondary seal, and combustion
gas which leaks from the seal ring 10 can be surely sealed by the
seal washer 11. Accordingly, a sealing ability of the whole
combustion-gas seal is improved, and an excellent sealing ability
is realized for a long term.
Moreover, the position at which the seal ring 10 is installed may
be set, by providing the seal washer 11 as a secondary seal, at a
position toward the tip of the fuel injection valve 5 (toward the
right-hand side in the drawing), because the allowable damaged and
leakage ranges of the seal ring 10 itself may be extended. Then, an
advantage that temperature rise at the tip portion of the fuel
injection valve is controlled may be expected.
Furthermore, as the fuel injection valve 5 is fastened into the
cylinder head 4, the seal washer 11 is simultaneously sandwiched
(assembled). Accordingly, only the seal ring 10 is assembled as a
seal onto the fuel injection valve 5 itself without increasing
steps for assembling the seal onto the fuel injection valve 5
itself. That is, addition of the seal washer 11 does not cause
reduction in the productivity.
According to the configuration of the present embodiment, a
highly-reliable combustion-gas seal with advantages including both
those of the combustion-gas seal according to the first embodiment
and those of the above-described seal washer may be provided.
DESCRIPTION OF REFERENCE NUMERALS
2, 3 Combustion-gas seal for fuel injection valve 4 Cylinder head 5
Fuel injection valve 6 Installing jig 7 Correcting jig 10 Seal ring
11 Seal washer 11a Metal ring 11b Rubber-like elastic portion 12
Heat-resistant ring 40 Mounting hole 41 Step surface 51 Annular
groove 52 Tapered portion 53 Step surface 54 Second annular groove
70 Correcting hole 71 Base 72 Correcting jig assembly
* * * * *